After a recent HD loss, and general lack of diskspace, I've decided to backup working Gambase installations to DVD rather
than keeping all the inital game download, plus various updates etc.

Whilst doing this, I started wondering of the zip's were actually compressed as effciently as they could be. I'd used
ZipMAx before with my Mame collection, and it did make a bit of a difference.

(ZipMax uncompresses a zip archive, then re-compresses the file(s) with a list of user defined packers. It then creates a new zip file with the most compressed file(s) from the original and resulting zips, in order to produce the smallest possible zip file - whilst maintaning 100% ZIP compatibility.)

After a lot of experimenting with various packers, and different inputs/switches, (details of which are towards the bottom
of this essay,) I obtained the above results. These are the best which I'm able to get by using a reasonable amoung of packers - ie 2!!

NOTE
This may seem a bit strange, but I wouldn't reckomend re-packing your existing zips.

It took me just over 2 days of constant use, on a dual-core machine, with fast-user switching enabled with 2 sessions, each session running Zipmax and the cpu was at 100% all of the time!

Although, the screenshot/PNGGauntlet maybe worth a try - as it didn't take that long.

However - the reason for posting this is because it maybe useful for new releases of Gamebase Amiga and also the KG's WHDL
releases. Eg the "GameBase Amiga - Rare Games (Update v1.4 to v1.4.3).zip" was 13.2MB. After repacking, it was 12.8MB. (Ok,
not that much but it's an average saving of 14K per *already ready* compressed file - which I think is pretty good.)

Here's how to do it(Make sure you have a backup first in case it goes wrong!!!)

Click the "Zip Test (general)" btton. This will then scan that dir + sub dirs, looking for zips and then tests them with 7-zip. (I know that 7zip integrated with explorer has a test button - but it dosn't do the
recursive checks).

This will then flag an issues with your existing zips

Next step - DeflOpt

Locate 7za.exe - either from "c:\temp\GBStFix_20\7ZIP\7za.exe" or whereever.

Open a command prompt - start->run->cmd (or start->run->command for 9x)

cd c:\temp (or wherever DeflOpt207.7z is located).

"G:\Gamebase\GBStFix_20\GBStFix_20\7ZIP\7za.exe" X DeflOpt207.7z

(this will extract deflopt.exe and txt to c:\temp in this case)

Next step - ZipMax
Extract ZipMax051.zip. Ie c:\temp\ZipMax\.
Copy 7za.exe into the same dir as zipmax.
Copy kzip.exe into the same dir as zipmax.

I've attched by zipmax.ini file - although you'll need to rename it back to ini as .ini isn't a valid upload file type for this forum.

Optional next step
Start a command prompt. Cd into a directory where deflopt.exe resides. Enter
DeflOpt /r "G:\Gamebase\GameBase Amiga\Screenshots\*.png"
this will knock a few extra bytes of the pngs.

Methodology (if your interested)

Re-used a tool which parsed the zipmax.log file and produced counts of which packer(s) produced the smallest file, which I
wrote when doing this for mame.
Wrote another tool which generated the cmd lines for 7za and kzip, with various switches. (Around 170 in total). Compressed
a test set of files and checked output. 2 packers were used most of the time, followed by 1 few more.
Took the top 3 and used on a started on the sps. Checked the ouput once about half way through, and decided that no.3
wasn't been used often enough and removed it.
Compressed rest of the zips using 2 packers.
Took a few re-compressed files and then tried re-compressing with the original master list, and a few other options. I've
found another kzip combination with saves a few bytes in around 50% of cases.

I only re-zipped the whdls as used in Gamebase amiga, as specified in the "GameBase Amiga - Move WHDLoad (v1.4.3).bat". I then cross referenced that list with your dat file "Commodore Amiga - Games - WHDLoad (KGWHD-v2007-09-11_CM)" - and removed :-

BackToTheFuturePart2_v1.2_0005.zip
KillingGameShow_v1.1.zip

as these weren't present in your dat fle. I was working on the assumption that if you have a dat file - then the contents of that dat must have windows legal file names.

The 36M saving was just on 1390 whdls from gamebase Amiga - I bet it'd been a bit more if it was run on the 1800'ish files in the cmpro dat file.

I've tested a few whdl's after the re-packing and they seemed ok.

I thought I'd post this info as it might be useful for future releases...